DE 197 00 980 A1 discloses an electromagnet valve of the generic type which, due to the simple design chosen, can exclusively adopt the function of a two-position valve of bistable operation.
Proportional electromagnet valves are also known which, however, necessitate considerable efforts in terms of control technology and construction. An electromagnet valve of this type of construction is described in DE 196 538 95 A1.
The generic application DE 42 44 444 A1 discloses an electromagnet valve which includes a spring element with a non-linear characteristic curve between the magnet core and the magnet armature. The spring characteristic curve extends steeper than the characteristic curve of the stroke force of the magnet armature, and both characteristic curves respectively reach their maximum value when the smallest air slot between the magnet armature and the magnet core is reached.
FR 2626711A discloses an electromagnet which includes a resetting spring and a flexible washer between a magnet armature and a magnet core. The washer is made of a non-magnetic material to prevent sticking of the magnet armature on the magnet core due to remanence after the electromagnetic energization. Therefore, the washer is ineffective over almost the entire magnet armature stroke and not either in the last part of the magnet armature stroke produces a counterforce that weakens the magnet force.
U.S. Pat. No. 3,653,630 also discloses the arrangement of a non-magnetic spring washer between the magnet armature and the magnet core to overcome the force between the magnet core and the magnet armature which is caused by remanence. To this end, the spring washer is spaced from the magnet armature to allow an unhindered stroke of the magnet armature. Under the condition that the magnet armature deforms the spring washer in the direction of the magnet core, the spring washer produces a release force that counteracts the remanence in order to speed up the magnet armature in reassuming its original rest position.
In view of the above, an object of the present invention is to improve upon a bistable electromagnet valve of the generic type and maintain a simplest possible design in such a way that the valve may also be operated as an analog valve or proportional valve, respectively, for volume flow control purposes.